Improvement in grinding-m ills



No. 50,274. Patented oct. 3, 1865.

Y"UNrTar-r STATES PATENT OFFICE.

JAMES O. ROBERTS, OF ADAMSTOWN, MARYLAND.

IMPROVEMENT IN GRINDINGMILLS.

Specification forming part of Letters Patent N0. 50,274, (lated OCtOber3, 1865.

To all whom it may concer/a:

Beit known that I, JAMES C. ROBERTS, ot

y Adamstown, in the county of Frederick and ings,which are made part ofthis specification,

and in whichy Figures 1 and 2 are side elevations of the framesupporting the stones and of the attached devices by which the runner isregulated. Fi g. is a central vertical section on the line .fr Fig. 1.Fig. i is an enlarged view of the uut and screw, the latter rotating'toelevate or depress the bridge-piece on which the spindle ot the runneris imposed. Fig.5 is an elevation, and Fig. 6 a top view,of thedouble-bitted dog and cog-wheel, the former engaging the latter by oneor the other of its bits, according to the direction ofrotation ofthecrank-shaft on which the bits are keyed.

Similar letters refer to corresponding parts in the different gurcs.

The object of my invention is to cause the runner when adjusted to grindat. a given weight for the production of a certain amount of Hour tomaintain its set, notwithstanding the varying expansion of .the spindle.

It is manifest that when the spindleis heated it becomes elongated, andwhen it has a detinite and unyielding bearing upon the bridgepiece bythe said expansion the ruimer is lifted and the set is lost.

My improvement is designed to lower the bridge-piece, which supports thespindle on which the runner is poised, so as exactly tomalie up for thesaid elongation ofthe spindle and maintain the stone at the setrequired,the reverse operation taking place on the cooling ot' saidspindle. Theliftingot' the runner adds to itsweight upon thebridge-piece as it is borne up to a less extent by the grain, and thisvariation in weight is caused to deliect a scaleheam and move a crankwhose shaft, through the medium of adouble-bitted dog andconnecting-gears,lowers the outer or movable point of suspension of thebrid ge-piece and restores the runner to its proper relational distancefrom Wille bed-stone.

To enable one skilled in the art to which my improvement is allied toconstruct and use the same I will proceed to describe it.

A is the frame, on which the bed-stone B is planted, and O is therunner, supported bythe spindle D upon the bridge-pieceE, oneof whoseends is hinged at F and the other supported by the screw-rod G,wheel-nut H, and rod I from the sale-beam J, which derives its supportfrom the frame at K. This describes in brief terms the support of thebridge-piece, but from what has already been said it is evident that ameans must be provided for moving the point E ot' the bridge-piece asthe spindle D contracts or expands, and this is accomplished by means tobe now described.

The required pressure of the runner being graduated by the weight L onthe scale-beam J, and the mill being set in operation, should thespindle becomeeelongated the short end ot' the beam J will he depressedand the otherend, j, will be raised, rotating the crank M, whoseshaftNcarries a dog with two bits, O O. The said motion throws one ofthe said bits into engagement with cog-wheel P.

At the end of the scale-beam J is a hanger, m, having a slotin which thewrist of the crank M works hack and forth under the motion ot'thevibrating arm V, the said oscillating motion not disturbing thehanger, but the elevation of the hanger m raising and lowering thewrist.

So much for the means of bringing the bit in contact with the wheel; butnow to describe the means by which it moves the said wheel.

On the spindle D is a bevel-gear wheel, Q, which gears into a wheel ofsimilar character,

R, on a shaft, S, on which is an eccentric, T,l

giving a reciprocating motion to a connectionrod, U, and vibrating aframe, V, which has an oscillating motion on a center, WV, land carriesat its upper end the shaft N and the doublebitted dogO O above spokenot'. This frame, through the means described, has a constant oscillatingmotion, and the dog is constantly hovering over the wheel P and so longas the given adjustment is maintained failing to engage with the cogsofthe said wheel; but when, from the causes above adverted to, the shaftN is rotated in either direction, then one or the other bit descends,and coming in contact (Fig. 5) with the wheel gives it a partialrotation, which is continued on the recurrence of the stroke of theframe'V until the'inciting cause is exhausted by the runner assuming therequired proximity to the bed-stone by means of the devices, which Iwill now describe, which connect the said cog-Wheel P with the WheelnutH, and by rotating it raise or lower the screw-rod G and lthebridge-piece E, which is supported thereby.

On the shaft ot' the cog-Wheel P is a bevelgear Wheel,X, which gearsinto awheel of similar character, Y, and that by means of the spurwheelZ on the same shaft rotates the Wheelnut H by engagement with its teethh.

The runnerjs driven by a band upon a pulley (not shown) on the shaft S.

The operation of the machine has been incidentally' described in thecurrent description of the parts, auditis believed to be sufficientlyclear. In general terms itis as follows: Supposing the mill to be set inmotion,thelength ening ofthe spindle due toits becoming.;` heated raisesthe runnerfarther from the bed-stone and 4increases its pressure uponthe bridge-piece. The increased weight raises the long end ofthescale-beam, and by intervention ofthe hanger partially rotates the crankon which the double-bitted dog is attached, the appropriate bitrotatingthe cog-Wheel which connects with the wheel-nut, and by rotatingit causes it to aseend on the screw-rod from which the bridgepiecedepends, lowering; the latter and with it the runner. An adjustablespring may be sub-A stituted for the Weighted scale-beam. The coolingofthe spindle reverses the motion andthe falling of the longer arm ot'the scale-beam throws the other bit of thedog in connection with thewheel to rotate it in the other direction and raise the bridgepiece.

Having thus described my invention, what I claim as new, and desire tosecure by Letters Patent, is-

l. The vibrating pawhframe or its equivalent7 operated from the drivingpower of" the mill, in combination with the interposed gearing andadjustable suspensionrod for raising or lowering the bridgepiece.

2. The Weighted scale-beam or its equivalent,from which the bridge-pieceis suspended and whose oscillations on either side oi' the given pointof adjustment actuate the mechanism for raising and lowering thebridge-piece.

3. In this connection and automatically operated, the rods G and I andwheel-nut H, forming a suspension rod adjustable as to length for thesupport of the movable end of the bridge-piece.

JAMES C. ROBERTS.

Vitnesses:

ELIAS SPALDING, Jus. L. ROBERTS.

